Eating qualities include flavour, firmness, texture and skin traits.

Flavour

Flavour is conferred by five main components, four of which vary from high to low. These latter are: Tannin, acid, sugar and ‘aromatics’. Tannins are complex phenolics, the acid is dominated by malic acid and the sugars are typically in the proportion fructose: (glucose+sucrose) 7:3. ‘Aromatics’ are diverse and numerous biochemicals present in small quantities that add to the flavour. The term is loosely used: aromatics are not particularly volatile and add little to aroma.

These four flavour components are released with the juice, typically when the flesh of the apple is crushed in the mouth. The fifth flavour component is the skin, which may be tough and obtrusive as in ‘Idared’ or slightly abrasive as in russets like ‘St Edmund’s Pippin’; in at least one variety, ‘D’Arcy Spice’, the skin has a hot peppery character.

Cider apples have a high tannin content, making them bitter or astringent when eaten fresh. They are subdivided into bittersweets, bittersharps, sweets and sharps. Some of the latter two categories (relatively low in tannins) serve as eating or cooking apples, when they have a distinctive tang, and some yield fresh juice (eg. ‘Kingston Black’ with a pleasing flavour).

Culinary varieties are acidic, tasting sour when eaten fresh, while the acid helps the flesh to break down into a puree on cooking.

The flavour of many dessert varieties is also classified by the character of their acidity by Morgan & Richards (1993), although this subjective character is no doubt conferred by aromatics in association with acid. Savoury or brisk dessert apples have a sufficiency of acid without being conspicuously sweet, giving them a brisk or savoury character like ‘James Grieve’. Such varieties are sometimes described as ‘dual-purpose, being suited to cooking early in their season and mellowing to a dessert character later. A berry-like acidity, as in ‘Discovery’, gives a sprightly character, while those varieties with pineapple-like acidity have a bold sweet-sharp character. All of these are strongly flavoured.

 Many varieties have a sufficiency and good balance of acid and sugar without much aromatic or other character (eg. ‘Falstaff’), while aromatic varieties vary in character from ‘lightly aromatic’ (eg. ‘Epicure’) to ‘intensely aromatic’ (eg. ‘Ribston Pippin’). The term ‘aromatic’ is sometimes used loosely to mean ‘like ‘Cox’s Orange Pippin’’, although aromatics also give character to other flavour categories such as ‘nutty’ (eg. ‘Blenheim Orange’), ‘sere russet’ (eg. ‘Egremont Russet’) and ‘aniseed’ (eg. 'Ellison’s Orange’) which are thought to reflect an increasing concentration of the aromatic estragol.

Apples characterized by low acids relative to sugars are described as ‘honeyed’ (eg. ‘Golden Delicious’) and ‘vinous or scented’ (eg. ‘Spartan’) by Morgan and Richards (1993). Like aromatic apples, ‘vinous or scented’ refers to flavour, not aroma. ‘Honeyed’ and ‘vinous or scented’ flavours are very sensitive to ripeness, so that their pleasingly delicate character is easily lost.

As well as varying beween varieties, flavour (and other eating qualities) also vary within a variety according to ripeness and time in store, site conditions and weather during the growing season.

The acid in apples of all flavour categories, once picked, tends to fade in store so that stored apples become subjectively increasingly sweet and other components of flavour can become increasingly evident, often leading towards a luscious character. Some varieties require a favourable site and a long and sunny season (eg. ‘Braeburn’) to reach their best development so the flavour of these, on some sites or in some years, can be disappointing.

Other eating qualities

Apples are typically hard before they ripen and become less firm with time, eventually becoming soft. Juiciness is associated with a relatively loose texture that yields to the bite and allows the easy release of juice (as in many commercial varieties). Triploids such as ‘Bramley’ and ‘Jonagold’ have a relatively loose texture. In contrast, late home-grown varieties often have a relatively dense texture (eg. ‘Orleans Reinette’), probably associated with a high dry matter content, which is more substantial or chewy and tends to crack rather than yield to the bite. In a home store, juicy apples tend to go unpleasantly soft while denser apples remain appealing for longer even if they become somewhat spongy through water loss.

Reference

Morgan, J. and Richards, A. (1993). The Book of Apples. The Ebury Press, London. ISBN 0-09-177759-3.